Virtualization of Balise Functionalities by Fibre Optic Sensing
The railway system uses balises as part of the physical infrastructure. The devices work similarly to a milestone and help determine train positions precisely and reliably: Whenever a train passes one of the balises, they transmit a compact message (telegram), which includes their balise information. Within the European Train Control System (ETCS), the balises implement a key functionality through this locally and timely restricted positioning. They guarantee a minimum accuracy for the positions calculated based on the movement and velocity data of the train (odometry).
A virtual balise system avoids the extensive use of physical devices. Instead, virtual balises employ alternative technologies to determine train positions. The research project explores the potential of FOS technology: Fiber Optic Sensing exploits local vibration measurements by optical fibers in cables alongside the tracks.
The project includes the construction of a test system and evaluation of the system's capabilities. Subsequently, it analyzes those aspects of the balise functionality that the FOS technology does not provide directly:
The processing of a global instead of several local measurements, the association of measured signals and trains, movements close to or outside of the FOS capabilities, or handling reduced guarantees and disruptions of data transmissions - they translate to special requirements for the virtual balise system.
For positioning on tracks without physical balise infrastructure, the project aims at achieving the required accuracy and reliability using the virtual system. A fully functional virtual balise system will contribute to a less expensive infrastructure, flexible train operation, and a significantly higher track capacity.